Electric nail drivers are more and more popular to the workers since they can make the people drive nails easily. In the prior art, the electric nail drivers have security switches for preventing the carelessness of people. When a trigger switch is pressed, the nail is beaten. If the security switch does not close, the trigger switch is actuated again, a nail will be beaten. Then, it is possible that an accident occurs. Thereby, the prior art security switch cannot protect a preferred protection.